Molybdenum alloying compound



Patente d Aug. 14, 1928.

UNITED STATES.

PATEQNT OFFICE.

EMIL A. LUCAS, OF WASHINGTON, PENNSYLVANIA, ASSI GNOR TO MOLYBDENUM CORPORATION OF AMERIECA, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELAWARE.

1T0 Drawing.

An object of the invention is to provide.

a coherent molybdenum composition, which,

when introduced into a molten bath of metal,

may be readily and quickly reduced and its entire molybdenum content quickly and thoroughly brought into contact with the molten metal for alloying with it. 1 A further objectis to provide a molybdenum alloying composition which may be manufactured and used with little, if any, loss of molybdenum. V k A further and more specific object is to provide a molybdenum alloying composition in which the molybdenum is present com bined' chiefly with oxygen, and which composition includes a material which acts as a fluxing agent when the composition is used for its intended purpose. The composition provided according to this invention comprises a fused coherent hard mass having a low fusion point in comparison with substances with which it is desired to alloy molybdenum, and containing molybdenum combined chiefly with oxygen, the

molybdenum oxides preferably being for the most part lower in oxygen content than molybdenum trioxide. In the broader aspects of the invention the combined molybdenum may constitute all or substantially all of the composition, but preferably the composition includes a suitable fluxing agent which has a low fusion point and .acts,as a carrier of the molybdenum protects the molybdenum against sublimation when the composition is introduced into a bath,

of molten metal, facilitates spreading of the composition in a 'fluid state upon a bath of molten metal so that the molybdenum when reduced may be disseminated throughout the bath, and carries off certain products of reduction of the molybdenum oxides. When the composition, includes such a fluxing agent, the molybdenum is held in solid solution in the free or combined state by the fluxing a ent, and 'is distributed substantially uni ormly throughout the mass. The

' fluxing agent'may include a lime, iron oxide,

silicon, and the like.

MOLYBDENUJVI ALLOYING- COMPOUND,

App1ication filed December 30,1924. Serial No. 758,916.

magnesia, silicate or fluoride, or mixture of silicate and fluoride, with small quantities of alumina forming a calcium, magnesium, aluminum, iron molybdenum silicate, or silicate and fluoride. The elements and the amounts of each which enter into'the format1on ofthe fluxing agent may be chosen to meet the different requirements of operating conditions, as will presently be explained.

In all forms of the composition the molybdenum is present in combined form. While as stated it is combined chiefly with oxygen, some of it may be combined with iron or with other elements present in the composition, particularly when it includes a fluxmg agent. For example, in the manufacture of the composition in an electric furnace under its usual reducing conditions, some of the molybdenum may be reduced to metal and ma then combine with the metals of other oxi es which are present and'are similarly reduced, such as iron, manganese, I Also, all forms have a low fusion point, usually between 1200 and 1300 0., but in all cases lower than the bath into which the composition is introduced. 4

The nature of the invention may be further understood from an explanation of the manner in which the composition acts when used f0r alloying molybdenum with steel. When the preferred form of the composition is placed upon or otherwise introduced into a bath of molten steel, the composition quickly melts due to its low fusion point, and being quite fluid it readily spreads for subsequent reduction and dissemination of its molybdenum content throughout the molten metal. The fluxing agent acts to prevent sublimation of such molybdenum trioxides as maybe present in the composition, and prevents further oxidation and consequent sublimation of the lower molybdenum oxides of-the composition. Reduction of the molybdenum oxides is effected by the action of carbon, manganese, silicon and other reducing agents that are present in the bath, and the products of such reduction as is effected by manganesa silicon, and the like, are carried off by the fluxing agent. As soon asreduction of the molybdenum oxides takes place the molybdenum-becomes absorbed by the bath and alloyed with it.

When a composition which contains little From the foregoing it is apparent that the composition may include any desired amount .of fluxmg agent, or may include none except that. present as an impurity. However, .as previously stated, the composition preferably does include a fluxing agent, and 1t preferably includes suflicient fluxing agent to act in the manner described when the composition is introduced into a bath of molten metal.

When in the preferred form of the composition a fiuxing agent is added to the molybdenum oxides, the materials chosen for forming the fiuxing agentyand the quantities of them, are preferably such asto result in a neutral or substantially neutral composition which may be used in either a basic-or acid process of manufacture with out attacking furnace linings, and without otherwise impairing or prejudicially affecting the conditions of operation. However, if desired, the materials forming the flux- .ing agent, and their qualities, may be chosen to form either a basic or an. acid composition for use, respectively, in a basic or acid process of manufacture.

By way of example, and not of limitation, a suitable neutral composition for use .in either an acid or basic process of'steel manu- 'facture may contain by analysis about 35% molybdenum combined chiefly with oxygen, about 22%, of calcium oxide, about 3% calcium fluoride, about 15.5% silica,'and about 9.0% iron oxide, with small percentages of magnesia and alumina, the remainder being oxygen mostly combined with molybdenum. The calcium magnesium iron oxide content of this composition being basic, neutralizes the silica which is acid, and therefore the composition may be usedin either an acid or basic'process of manufacturin steel without attacking furnace linings whlch in the former are acid and in the latter are basic.

When a baslccomposition 1s desired for use in a basic process of manufacturing steel,-

it. may contain by analysis about 35% mo lybdenum,-about 29% iron oxide, about 10% silica, about 8% calcium oxide, and about 3% calcium. fluoride, the remainder being small percentages of the elements mentioned with reference to the first example.

The calcium and iron oxide content of the compositlon render-it basic, sogthat when used in a bas1c process of steel manufacture thecomposition will not'attackthe furnace lining. Some of the iron may be replaced with calcium oxide so that the basic content of fluxing material may, for example; be.

about 29% calcium oxide and 9.0% iron oxide.

When an acid composition is desired for usein an acid process of manufacturing steel, the composition may contain by analysis about 35% molybdenum, about 15% calcium oxide, about 22% silica, about 9.0% I

iron oxide, and about 3% calcium fluoride, the remainder being some or all of the ingredients mentioned with reference to the first example. Silica being the predominant fluxing agent ingredient, the composition is acid and does not attack the acid lining of a furnace.

While the composition may be variously manufactured, it is preferably produced according to the method disclosed in my co pending patent application Serial No. 758,- 917 filed of even date herewith. As therein disclosed, thecompound may be made from molybden'ite by roasting a suitable concentrate thereof to remove its sulphur con tent, and subsequently fusing the roasted mass. When the preferred form of composition is so made, that is to say a composition including a fluxing agent, the ma-.

terials for forming the fluxing agent are" added to the roasted 'molybdenite and are As is also disclosed in the said application, when it is desired tomanufacture the composition from lead molybdate, that is to say wulfenite ore, the oremay, without pre-. vious roasting, be heated in the presence of the fluxing agents previously described. This results in reducing the lead to metal which settles in the bottom of thefurnace, andin producing the fused composition as molten slag which may be tapped ofl.

, The composition maybe produced economically withoutloss of molybdenum, and may be used in alloying operations without loss of molybdenum. As to the latter, in actual use of the composition it has been found that steel may be produced containing all but a Very small fraction of 1% of the molybdenum content of the composition introduced into the steel bath. This is due, among other things, to three important the fusing operation characteristics of the composition, first, its

coherentphysicalstate which eliminates loss by dusting, second, the fact that the molyb- 4 ments of it.

makes it easy to determine the molybdenum content of a given weight' of the-composi tion, and third, the ease with which .the molybdenum is reduced. It follows that, by the use of the composition, steelmay be produced containing,.within very narrow variations, a predetermined content of molybdenum. The use of the composition has further shown that there results a superior quality of molybdenum steel free from segregations.

Accordin to the provisions of the patent statutes, I

ave described theprinciple of my invention and the manner in which it may be used, together with specific embodi- However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced with compositions other than those particularly described and by compositions produced otherwise than by the methods disclosed herein. Y

'I claim as my invention: 1

1. A composition for alloying molybdenum with another metal, comprising a mass fused from a mixture of molybdenum oxide and(- a flux-forming oxide, the mass containing molybdenum oxides lower in oxygen content than molybdenum trioxide.

2. A composition for alloying molybdenum with another metal, comprising a mass fused from a mixture :of molybdenum oxide and a flux-forming oxide, the mass containing molybdenum oxides lower in oxygen content than molybdenum trioxide, and also containing a calcium molybdenum silicate.

3. A composition for alloying molyb denum with another metal, comprising a mass fused from a mixture of molybdenum' oxide and a flux-forming oxide, the mass containing molybdenum oxides lower in oxygen content than molybdenum trioxide, and also containing a molybdenum silicate and fluoride.

.4. A composition for alloying molybdenum with another metal, comprising a mass fused from a mixture of molybdenum oxide and afiux-forming oxide, the mass containing molybdenum oxides lower in oxygen content than molybdenum trioxide, and also containing a calcium iron molybdenum silicate.

5. A composition for alloying molybdenum with another metal, comprising a mass fused from a mixture of molybdenum oxide and a flux-forming oxide, the mass containing molybdenum oxides lower in oxygen content than molybdenum trioxide, and also containing a calcium iron molybdenum silicate and fluoride.

In testimony whereof, I'sign my name.

EMIL A. LUCAS; 

